Wednesday, February 16, 2005
The highest energy physics
Greetings from Aspen, where tonight I'll be giving a public talk on Dark Matter and Dark Energy: From the Universe to the Laboratory. It's at 8:00 pm, any blog readers in the neighborhood are encouraged to drop by. The talk is part of the Aspen Winter Conference on The Highest Energy Physics, which is in turn part of a sequence of annual conferences held at the Aspen Center for Physics. Physicists know how to live, I tell you.
Right now the highest-energy physics we have here on earth is being conducted at Fermilab, a short drive from Chicago. The Tevatron accelerator is crashing protons into antiprotons to see what comes out. The hope is that we see something good like the Higgs boson, or supersymmetry, or large extra dimensions of space. If not, the Large Hadron Collider at CERN in Switzerland is scheduled to turn on in 2007, and will be operating at notably higher energies. There's almost a guarantee that the LHC will see something interesting, although of course you never know what until you look.
In the meantime, you are welcome to go look at the actual events at the Tevatron in real time! The two main experiments, CDF and D0, both have displays where you can see live events. I wish there was a little more explanation about what the displays actually mean; right now it's more gee-whiz than really being informative. But still, pretty gee-whiz; this is a schematic of the cylindrical volume of the CDF detector, with all those curly lines representing particles produced by a collision.
Of course, there are much higher-energy particles that are not made on Earth, namely ultra-high-energy cosmic rays. These are being observed by the new Pierre Auger observatory, which has a facility in Argentina and hopes to build another in the U.S. The analogy I will use tonight is that particle astrophysics and collider physics are like eavesdropping and interrogation. When you eavesdrop on someone, they might reveal things that they would never tell you outright; similarly, the ultra-high-energy cosmic rays could teach us something about particle physics that we couldn't get to by accelerating particles ourselves. But the problem with eavesdropping is that you can't just ask the questions you want to; besides, most of the time the conversations you overhear are just boring. If you are interrogating someone, perhaps they will clam up about some interesting questions, but at least you can be precise about what you are asking. And who knows, they might just tell you the answer.